Spiranthes diluvialis Survey, 2003

Final

ROCKY REACH HYDROELECTRIC PROJECT FERC Project No. 2145

November 1, 2003

Prepared by: Beck Botanical Services Bellingham, WA

Prepared for: Public Utility District No. 1 of Chelan County Wenatchee, Washington

Rocky Reach

TABLE OF CONTENTS

SECTION 1: INTRODUCTION ...... 1

SECTION 2: METHODS...... 1

SECTION 3: RESULTS AND DISCUSSION...... 2 3.1 Chelan and River Populations ...... 2 3.2 Howard Flats Population...... 2 3.3 Gallagher Flats Population ...... 3

SECTION 4: CONCLUSIONS ...... 3

SECTION 5: REFERENCES ...... 4

Spiranthes diluviali Survey Final Report Rocky Reach Project No. 2145 November 1, 2003 Page i SS/8499 Rocky Reach Spiranthes diluvialis

LIST OF TABLES

Table 1: Spiranthes diluvialis numbers for three populations on the Rocky Reach of the Columbia River, 2000 – 2003...... 2 Table 2. The Howard Flats Spiranthes diluvialis populations broken down by area, 2000 – 2003...... 2

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SECTION 1: INTRODUCTION

Three populations of Spiranthes diluvialis (Ute ladies’-tresses) were discovered on the upper end of the Rocky Reach Reservoir in August 2000. Rocky Reach Dam is owned and operated by the Chelan County PUD. S. diluvialis is an orchid species listed as Threatened under the Endangered Species Act (ESA) currently known from Colorado, Idaho, Montana, Nebraska, Utah, Washington, and Wyoming. It was listed by the U.S. Fish and Wildlife Service in 1992 because of a variety of factors, including habitat loss and modification, and hydrological modifications of existing and potential habitat areas (USFWS 1992). Its status in Washington is Endangered (WNHP website 2003). Besides the three closely situated Rocky Reach populations, there is only one other known population of S. diluvialis in Washington.

Spiranthes diluvialis is endemic to mesic or wet meadows and riparian/wetland habitats near springs, seeps, lakes or perennial streams. Soils may be inundated early in the growing season, which normally become drier but retain subsurface moisture through the season. S. diluvialis occurs primarily in areas where the (overstory) vegetation is relatively open and not dense or overgrown (USFWS 1995). S. diluvialis is a late-blooming species, which is only recognizable while it is blooming. Despite their distinctive spikes of white , blooming can be extremely difficult to see in the dense herbaceous understory vegetation with which they are associated. Plants not yet blooming, plants past bloom, and vegetative plants are virtually impossible to distinguish from background vegetation. Because plants come into bloom at different times within a single population, a population must be visited several times during the growing season for an accurate count. Within the Rocky Reach project area, plants are typically in bloom from mid-July to late- August. Because of its status as a Threatened species, several survey visits were planned to fully map and census the three Spiranthes diluvialis populations on Rocky Reach. An accurate annual census provides information about the viability of the populations and their habitat over time.

SECTION 2: METHODS

In 2003, the three Rocky Reach Spiranthes diluvialis populations were censused on July 18 and August 25. They were accessed by boat during times the orchid species is known to . Surveys consisted of careful visual searching for, and counting of, individual plants in known locations and in appropriate nearby habitat. Population counts are comprised primarily of blooming plants, as vegetative or non-flowering plants are typically very difficult to see. When seen, vegetative plants are included in counts. The three populations have been surveyed yearly since 2000.

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SECTION 3: RESULTS AND DISCUSSION

Although 2003 was a very hot, dry summer, snowpack for the previous winter was in the normal range. Overall, 2003 seemed to be a favorable year for population numbers (Table 1). The total number of plants for the three combined populations was slightly higher than 2000, the year that had the most similar river levels and weather patterns to 2003. Due to a drought, 2001 had much lower than average river levels, and 2002 had much higher than average river levels. Both weather regimes presumably affected population numbers for the year.

Table 1: Spiranthes diluvialis numbers for three populations on the Rocky Reach of the Columbia River, 2000 – 2003 # Population Name 2000 2001 2002 2003 1 Chelan Pond habitat 110 69 51 154 River habitat 75 2 77 24 2 Howard Flats 60 0 46 58 3 Gallagher Flats 7 0 1 19 Total # of plants 252 71 175 255

3.1 Chelan and River Populations Although 2003 was a very hot, dry summer, snowpack for the previous winter was in the normal range. Overall, 2003 seemed to be a favorable year for population numbers (Table 1). The total number of plants for the three combined populations was slightly higher than 2000, the year that had the most similar river levels and weather patterns to 2003. Due to a drought, 2001 had much lower than average river levels, and 2002 had much higher than average river levels. Both weather regimes presumably affected population numbers for the year.

3.2 Howard Flats Population The Howard Flats Spiranthes diluvialis population totals for 2003 are similar to 2000. While overall numbers between 2000 and 2003 are similar, the distribution of plants within the population has changed markedly (Table 2). The population has a north and a south portion, which are separated by several hundred feet. The north end is near the Columbia River shore, while the south end of the population is several hundred feet inland in a large moist meadow. In 2000, 30 plants were located at the south end of the population, while in 2003 only four plants could be located there.

Table 2. The Howard Flats Spiranthes diluvialis populations broken down by area, 2000 – 2003. North end 30 0 39 54 South end 30 0 7 4 Total 60 0 46 58

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Since the Spiranthes population was first surveyed in 2000, the size and density of the annual noxious weed species white sweet-clover (Melilotis alba) has increased dramatically, particularly in the south end of the population. In places, these plants form dense masses over six feet tall. Other weeds such as yellow flag, alfalfa (Medicago sativa), Canadian thistle (Cirsium arvense), and Russian ( angustifolia) have also become more prominent in and near the Howard Flats population. In addition, there is an increase in the number of flowering patches of purple loosestrife observed in the vicinity of the population every year. This increased weediness within the population may in part explain the decline in population numbers in the south end of the population, which may be attributed to the removal of cattle from the area since 2000. Seasonal grazing probably helped to control weed infestations in and near the Spiranthes population.

3.3 Gallagher Flats Population The Gallagher Flats Spiranthes diluvialis population (Table 1) had more than twice as many plants than had previously been documented. Most of these plants appeared to be quite vigorous and to have a relatively high number of flowers. Common St. John’s-wort (Hypericum perfoliatum) appears to be significantly less widespread in the vicinity of the population than was observed during the 1990 rare survey (F. Caplow pers. comm.).

SECTION 4: CONCLUSIONS

Overall, 2003 seemed to be a favorable year for the species, although there were areas within the populations that seemed to have significantly lower and/or higher numbers than previous years. Some of these intra-population fluctuations are not reflected by population totals. GPS coordinates are useful to map the intra-population areas and plant concentrations.

As stated previously, annual surveys for the Rocky Reach Spiranthes diluvialis populations will provide valuable trend data for viability of populations and related habitat. These surveys would continue to provide information about the effects of flooding, drought, river channel changes, and warmer and colder than average temperatures on plant numbers and the habitat of the three Spiranthes populations. While the changes in the Spiranthes populations’ environment listed above are not Project related, the data collected during monitoring activities will be valuable for assessing the status of these listed populations in the future.

On August 25, 2003, Jeff Osborn (Chelan County PUD), Steve Lewis (U.S. Fish and Wildlife Service), Florence Caplow (Washington Natural Heritage Program), Kevin Kane (BLM) and Julie Sanderson (BLM), Paul Fielder (Chelan County PUD), and Katy Beck (Beck Botanical Services) surveyed the Rocky Reach Spiranthes diluvialis populations. There were discussions of potential management and enhancements for each of the populations. These are listed below.

Chelan (Population 1) – The survey group dug and cleared the noxious weed yellow flag from four locations in and near the pond. Seedpods were cut off of plants on the pond margins. More cutting, digging and possible herbicide application is needed to control the dramatic increase of this weed. Purple loosestrife along the river appears to be increasing and could benefit from control.

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Howard Flats (Population 2) – If it is determined that noxious weeds are having a detrimental effect on population numbers at the south end of the population, some method of noxious weed control should be considered.

Gallagher Flats (Population 3) – Common St. John’s-wort appears to have decreased over the last ten years at this site. There does not appear to be a present need for weed control at this time. Bayer, J. and J. Seelye. Undated abstract. Upstream migration of Pacific lamprey (Lampetra tridentat) in the Columbia River. U.S. Geological Survey, Biological Resources Division, Cook, WA.

SECTION 5: REFERENCES

USFWS. 1992. Final Rule to List the Plant Spiranthes diluvialis (Ute ladies' tresses) as a Threatened Species. Federal Register. 57, 12: 2048-2054.

USFWS. 1995. Ute ladies'-tresses (Spiranthes diluvialis) recovery plan. Denver, Colorado: U.S. Fish and Wildlife Service.

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